Electrical switch



Aug. 25, 1959 D. E. CLARKE ELECTRICAL SWITCH 2 Sheets-Sheet 1 Filed Aug.16, 1957 [72 van tor;

Aug. 25,. 1959 D. E. CLARKE ELECTRICAL SWITCH 2 sheets sneet 2 FiledAug. 16, 1957 In van to); David 15: C'Zarii'e, a

United States Patent ELECTRICAL SWITCH David E. Clarke, Norton, Mass,assignor to Texas Instruments Incorporated, Attleboro, Mass, acorporation of Massachusetts Application August 16, 1957, Serial No.678,512

15 Claims. (Cl. 200-122) This invention relates to electrical switches,and more particularly, to such switches which incorporate a pair ofcooperating contacts relatively movable between open and closedpositions.

This invention represents an improvement over the inventionsrespectively disclosed and claimed in U.S. Patent No. 2,345,451, grantedMarch 28, 1944, to J. D. Bolesky, and in copending U.S. application,Serial No. 586,547 of W. W. Cardin et al., filed May 22, 1956 now PatentNo. 2,863,965.

An object of this invention is to provide an electrical switch havingimproved operating characteristics.

A further object of this invention is to provide an improved electricalswitch incorporating a unique arrangement for effecting rapid closing ofat least one pair of contacts thereof. A further object of thisinvention is to provide such a switch by which the contacts thereof wipeagainst each other during movement to closed position. A further objectof this invention is to provide such a switch which is simple,inexpensive to manufacture and dependable in operation.

A further object of this invention is to provide a resettable circuitbreaker incorporating a unique arrangement for effecting snap closure ofat least one pair of contacts thereof.

Other objects will be in part obvious and in part pointed outhereinafter.

The invention accordingly comprises the elements and combinations ofelements, features of construction, and arrangements of parts which willbe exemplified in the structures hereinafter described, and the scope ofthe application of which will be indicated in the following claims.

In the accompanying drawings, in which the invention is illustrated:

Fig. 1 is a plan view of an electrical switch embodying the presentinvention;

Fig. 2 is a view similar to Fig. 1 but with the cover plate andoperating handle removed;

Fig. 3 is a sectional view on an enlarged scale taken along line 3, 3 ofFig. 1;

Fig. 4 is a sectional view taken along line 4, 4 of Fig. 3;

Fig. 5 is a sectional view taken along line 5, 5 of Fig. 3;

Figs. 6 and 7 are similar to Fig. 3 but respectively show the movableparts of the device in an intermediate stage of operation and in theposition at which the contacts thereof are retained in closedrelationship; and

Fig. 8 is a fragmentary sectional view showing an alternative form ofactuating means for the switch.

Referring to the drawings, the numeral 10 generally indicates anelectrical switch incorporating the present invention. This switch takesthe form of a circuit breaker which includes a base or casing member 12.Base member 12 provides a hollow interior and is formed of a suit ableinsulating material such as one of the common molded plastics. A pair ofelectrical terminals 14 and 16, respectively, are carried by base member12. Ter- "ice minal 14 includes an overturned portion 18 upon which anelectrical contact 20 is mounted. Terminal 16 is provided with anoverturned portion 22, the latter being electrically connected to oneend of a heater 24 by any suitable means such as a weld at 26. Theopposite end of heater 24 is electrically connected, as by welding at28, to a support 30 for an electrical contact 32. It will be apparentthat when contacts 20 and 32 are electrically connected, an electricallyconductive path is established leading from terminal 14 through, insuccession, contact 20, contact 32, heater 24 and terminal 16. Support30 is secured to base member 12 by any suitable means such as a rivet34.

The use of a heater in association with a thermally responsive element(later to be described) is well known and its function need not bedescribed in detail. It will sufiice to note that such a heater addsheat to the thermally responsive element in addition to that developedin the latter due to the passage of current therethrough, and isgenerally utilized in installations having a relatively low currentrating. It will be noted that in those installations where such a heateris not required or desired it may be eliminated, in which case contact32 could be electrically connected to terminal 16 in a manner similar tothat by which contact 20 is electrically connected to terminal 14.

Base member 12 is provided with a socket 36 within which a sleeve 38 isdisposed. Disposed with a loose fit within sleeve 38 and guided formovement thereby is a headed shank 40. Head 42 carried by shank 40provides a cam surface 44 and a surface 46 engageable with the adjacentsurface of an inherently thermally responsive, snap-acting element 48.Element 48 provides an aperture 49 through which shank 40 extends. Themutually adjacent surfaces of head 42 and element 48 are ordinarilymaintained in engagement by means of a compression spring 50. As bestshown in Figs. 3, 6 and 7, one end of the spring is biased againstelement 48. The opposite end of spring 50 is biased against shoulder 54provided by sleeve 38, and part of this spring is disposed between areduced diameter portion 52 of sleeve 38 and a portion of the internalwall defining socket 36 in base member 12. Headed shank 40 issymmetrical on both sides of all planes within which the axis thereoflies whereby head 42 and the shank provide their intended functions inall positions of rotation thereof.

Inherently thermally responsive, flexible, snap-acting element 48 isformed of composite material and is of the type disclosed in U.S. PatentNo. 1,448,240, granted on March 13, 1923 to J. A. Spencer. By way ofexample, element 48 may take the form disclosed in copending U.S.application, Serial No. 497,109, filed on March 28, 1955, now Patent No.2,860,208. In response to a change in temperature thereof, element 48 issnappable from the downwardly bowed condition shown in full lines inFigs. 3, 4, 6 and 7 to the upwardly bowed condition shown in brokenlines in Fig. 7. In response to a sufficient temperature change in theopposite direction, element 48 is snappable from the upwardly bowedcondition to the downwardly bowed condition. A pair of mutually spacedcontacts 56 and 58 are carried in electrically conductive connectionwith element 48 through the intermediary of electrically conductivestrips or bars 57 and 59, respectively. Element 48 is movable, by meanslater to be described, from the upper, contacts-open position shown inFig. 3 to the lower, contacts-closable position shown in Fig. 7. In theupper position of element 48, contacts 56 and 58 are separatedrespectively from contacts 20 and 32, and in the lower position thereof,contacts 56 and 58 are engageable with contacts 20 and 32, respectively.

A ledge 60 is provided for a purpose later to become apparent. Ledge 60may be provided by the upper surfaces of a pair of mutually spaced,upstanding sections 62, 62 integral with base member 12. It will beclear that, although ledge 60 is shown in the drawing as being formed bytwo spaced surfaces, this ledge could be provided in the form of asingle continuous surface as well as in other forms. Ledge 60 isrelieved or sloped adjacent element 48 at 61. It will be noted that theinclination of portion 61 of ledge 60 is in a general direction towardcontact 32.

Mounted for rectilinear movement to the right from the position shown inFig. 3 is a slide 64. Slide 64 is confined laterally by the adjacentinternal surfaces provided by casing member 12, at its upper surface bycover member 66, and at its lower surface by a slide-supporting member68. Cover plate 66 can be secured to casing member 12 in any suitablemanner such as by screws (not shown). Slide-supporting member 68 is, inturn, supported at its ends by shoulders 70 and 72, and at its sides byshoulders 74 and 76, all provided by casing member 12. Slide 64 isbiased to the left as viewed in Figs. 2 and 3 by means of a compressionspring 78. Casing member 12 provides a pair of stops 80, 80 limiting theextent of movement of the slide toward the left as viewed in Fig. 2 anda pair of stops 82, 82 limiting the extent of movement of the slide tothe right.

Slide 64 carries a wear-resistant bushing 84 for the reception of oneend of a pin 86 carried by a toggle lever 88. Lever 88 is mounted forpivotal movement about a pin 90, the latter having its ends disposed inthe wall of an externally threaded, hollow cylindrical neck 92. Neck 92is carried by cover member 66 in position about an adjacent apertureprovided by the latter.

Slide 64 carries a cam-mounting member 94 which projects through anaperture 96 provided by supporting member 68. Member 94 mounts a ball 98for free rotation of the latter, the exterior surface of the ballproviding a cam surface 100 for cooperation with the cam surface 44provided by head 42.

An alternative form of means for actuating slide 64 is shown in Fig. 8.Except as specifically pointed out in this paragraph, the structure ofthe embodiment illustrated in Fig. 8 is identical with that of Fig. 3.The reference numerals of the parts shown in Fig. 8 which are or may beidentical with their counterparts in the remaining figures of thedrawing are the same as the reference numerals of the latter but primed.The embodiment of Fig. 8 includes a bell crank 102, the end of one leg104 of which is disposed within bushing 84 and the end of the other leg106 of which is disposed in an aperture 108 provided by the wall 110 ofa counterbored member 112. Bell crank 102 is mounted for pivotalmovement about pin 111, the latter having its ends secured in the wallprovided by externally threaded, cylindrical, hollow neck 114. The wallsof the lower end of member 110 provide a pair of slots 116 whichaccommodate pin 111 and cooperate therewith to guide member 110 and thestructure fixed thereto for vertical movement as viewed in Fig. 8.Fixedly carried by member 110 is a band 118 and a push button 120. Theparts are shown in Fig. 8 in the position corresponding to that shown inFig. 7. It will be apparent that depression of push button 120 from itsfully retracted position toward that shown in Fig. 8 effectscounterclockwise movement of bell crank 102 about the axis of pin 111whereby slide 64' is moved to the right. It is also noted thatcompression spring 78 resiliently biases slide 64 to the left as viewedin Fig. 8, whereby push button 120 is also resiliently biased to itsfully retracted position. Band 118 may be formed of a color orappearance contrasting with that of the adjacent portion of push button120, thereby clearly to indicate whether the respective pairs ofcooperating contacts of the device are closed or open. In this regard,when push button 120 is disposed but not forcibly held in the positionshown in Fig. 8, band 118 is hidden behind member 114 and contacts 56and 58 are engaged with contacts 20 and 32, respectively; and when thepush button is in its fully retracted position, band 118 is exposed toview and contacts 56 and 58 are respectively disengaged from contacts 20and 32.

Operation of the device as illustrated in Figs. 17 will now bedescribed. With the parts in the respective positions shown in Fig. 3,element 48 is in its uppermost, contacts-open position whereat spring 50resiliently biases the upper surface of head 42 against the adjacentportion of slide 64, element 48 is in the downwardly-bowed,contacts-closable condition, and slide 64 is in fully retracted positionagainst stops 80, under the influence of compression spring 78. Whenlever 88 is pivoted in a counterclockwise direction from the positionshown in Fig. 3, slide 64 along with ball 98 is moved to the rightagainst the bias of spring 78 to bring cam surface into engagement withcam surface 44. Sufiicient clearance is provided between the internalwall of sleeve 38 and shank 40 that upon continued pivotal movement ofthe lever, shank 40 tilts in a clockwise direction to bring theright-hand end of element 48 into over-hanging relationship with slopedsurface portion 61 of ledge 60. Headed shank 40 is depressed in thistilted relationship as ball 98 continues to move to the right, with theresult that the right-hand end of element 48 moves into overlappingengagement with sloping surface 61 and contact 56 is moved intoengagement with contact 20; this being the position of the parts asshown in Fig. 6. Upon further continued movement of ball 98 to theright, the latter moves against head 42 and continues to depress theheaded shank while in its tilted relationship until the cam surfaceprovided by the ball reaches the uppermost tip of cam surface 44provided by head 42. From the time that cam surface 100 first engagescam surface 44 until the former reaches the uppermost tip of cam surface44, it is apparent that the relationship between cam surfaces 100 and 44is such that the resultant force acting against element 48 is directedalong a line intermediate the directions in which element 48 is movablefrom contacts-closable to contacts-open position and in which theelement is movable laterally of this first mentioned direction under thetilting movement of headed shank 40. Also, during this time head 44 isdepressed against the bias of spring 50 and against the bias built up inelement 48 due to deflection of the central portion thereof relative toits respective end portions.

Head 42 provides an annular surface 124, into engagement with which camsurface 100 of ball 98 moves after leaving cam surface 44. Upon movementof cam surface 100 into engagement with surface 124, the lateralcomponent of force exerted to the right against element 48 as viewed inFig. 6 is released, and under the vertical force exerted by head 42against element 48 the latter shifts to the left as the end of element48 slides off relieved portion 61, contact 56 wipes against contact 20,and contact 58 snaps into engagement with contact 32.

The advantages of the contacts snapping to closed position as opposed tocreeping to closed position are well known to those skilled in the art.For example, if contacts 56 and 58 Were permitted to creep to closedposition it would be possible to burn out the switch or at least upsetits calibration due to over-heating by closing on a fault. That is, thetemperature at which element 48 snaps from contactsclosable tocontacts-open condition is substantially higher when the contacts firstmove into engagement than it is when element 48 is in the pulled-incalibrated position shown in Fig. 7. By snapping contact 58 intoengagetment with contact 32, the time during which contact 58 is inengagement with contact 32 and the element 48 is not in fully pulled-incondition is so very short that the calibrated temperature at whichelement 48 snaps to the contacts-open condition is reached beforedeleterious overheating occurs.

Upon continued movement of slide 64 along with ball 98 toward theposition shown in Fig. 7, ball 98 rides over the innermost edge ofannular surface 124 and into engagement with a catch provided by theopen end of a socket 126 in head 42. During the short interval afterball 98 moves off surface 124 and before it seats in catch 126, the ballexerts a lateral component of force through head 42 to the left againstelement 48 as viewed in Fig. 7 with the result that element 48 shiftsfurther to the left whereby each of contacts 56 and 58 wipes against itscooperating contact 20 and 32, respectively. The wiping action betweencontacts 56 and 2t and between contacts 58 and 32 results in an abradingaction tending to maintain the mating surfaces of the respectivecontacts in a clean condition free of dust, sulfides, oxides and otherforeign matter.

With ball 98 seated in catch 126, slide 64 is engaged with stops 82, 82provided by casing member 12 and the parts are in the positions shown inFig. 7. In a manner corresponding to that described above with respectto the push button shown in Fig. 8, when toggle lever 88 is in theposition shown in Fig. 7 but not forcibly held there, the respectivepairs of cooperating contacts of the circuit breaker are closed; andwhen lever 88 is in the position shown in Fig. 3, the respective pairsof coopcrating contacts are open.

With the parts in the positions shown in Fig. 7, the relationshipbetween the forces exerted by springs 50 and 78 and the element 48itself is such that catch 126 will retain ball 98 therein, and element48 will be retained in the contacts-closed position. In this regard, theforces exerted by element 48 and spring 50 produce a greater effecttending to maintain ball 98 within catch 126 than the effect of spring78 against slide 64 tending to release the ball from the catch andresult in movement of slide 64 to the right toward the position shown inFig. 3. However, the effect of spring 50 tending to maintain the ballwithin the catch is less than the effect of spring 78 tending to movethe slide to the position shown in Fig. 3, with the result that, iflever 88 is released in the position shown in Fig. 7 While the element48 is in its upwardly bowed, contacts-open condition, ball 98 will bereleased from the catch and slide 64 will move to its retractedposition. Furthermore, the force exerted by element 48 alone due todeflection thereof has a greater effect tending to retain ball 98 Withinsocket 126 than the effect of spring 78 tending to move the slide toretracted position, and the result is that the parts will be retained inthe positions shown in Fig. 7 under shock and vibration conditions.

When inherently thermally responsive element 48 responds to atemperature change by snapping to the upwardly bowed condition shown inbroken lines in Fig. 7, the force exerted by element 48 itself tendingto retain ball 98 within catch 126 is released, spring 78 overcomes theforce exerted by spring 50, and slide 64 moves to retracted positioncarrying ball 98 with it. With movement of slide 64 to the positionshown in Fig. 3, element 48 moves upwardly under the bias of spring 50until head 42 engages the adjacent surface of the slide, and lever 88pivots in the clockwise direction to the position shown in Fig. 3.

A unique feature of this invention lies in the fact that although ledge60 is disposed in interfering relationship with the adjacent end ofelement 48 to provide the snapclosing feature of contacts 58 and 32 uponclosing of these contacts, this interfering relationship does not existduring opening of the contacts for the reason that ledge 60 is disposedin spaced relationship to the path of the adjacent end of element 48during movement of the latter to contacts-open position andcontacts-open condition.

Calibration of the device can be eifected as follows. Base member 12provides a recess 128 which interfits with a nut 130 whereby the latteris retained against rotation relative to base member 12. Accessible fromthe exterior of base member 12 is a screw 132 threadedly engaged withnut 130. By rotation of screw into engagement with and againstoverturned portion 18 of terminal 14, the latter can be elevated tochange the height of contact 20 relative to the base whereby the amountof pull-in of the element 48 can be adjusted. This, in turn,correspondingly adjust the temperature at which element 48 snaps fromthe contacts-closable condition to the contacts-open condition.

In view of the above, it will be seen that the several objects of theinvention are achieved and other advantageous results attained.

The dimensions and size of certain of the parts as shown in the drawingshave been modified for the purposes of clarity of illustration.

As many changes could be made in the above constructions withoutdeparting from the scope of the invention, it is intended that allmatter contained in the above description or shown in the accompanyingdrawings, shall be interpreted as illustrative and not in a limitingsense.

I claim:

1. In combination; a casing, an inwardly extending ledge carried by saidcasing, a first electrical contact carried by said casing, an inherentlysnap-acting thermostatic element carrying a second contact, meansmounting said element for movement of the latter in first oppositedirections between a contacts-open position and a contactsclosedposition, said means permitting movement of said element in secondopposite directions laterally relative to said first opposite directionswhen said element is in said contacts-open position, and means forexerting a force against said element for first moving the latter in oneof said second opposite directions and toward said contacts-closedposition to bring a portion of said element into overlapping engagementwith said ledge and for then moving said element in the other of saidsecond opposite directions and to contacts-closed position whereby saidportion of the element snaps off said ledge and said first contact snapsinto engagement with said second contact.

2. In combination: a base; a first contact mounted on said base; asecond contact; an inherently snap-acting thermostatic element carryingsaid second contact; means mounting said element for movement in a firstdirection from a position at which said contacts are open to a positionat which said contacts are closed, said mounting means permittingmovement of said element in a second direction transversely of saidfirst direction; said element being movable in the direction opposite tosaid first direction from contacts-closed position to contacts-openposition; a ledge adjacent a portion of said element and spaced from thepath of said portion when the element moves from contacts-closed tocontacts-open position, and means for exerting a force against saidelement for moving the latter in said second direction and then in saidfirst direction thereby first to bring said portion of the element intooverlapping engagement with said ledge, said means thereafter movingsaid element in a direction opposite to said second direction to snapsaid portion off said ledge whereby said second contact snaps intoengagement with said first contact.

3. The combination as set forth in claim 2 wherein said first-namedmeans includes a shank; said shank being tiltably disposed in guidingmeans therefor.

4. The combination as set forth in claim 3 wherein said shank has a headfixed thereto; said head bearing against said element and providing acam surface for cooperation with said last-named means to exert saidforce against the element.

5. The combination as set forth in claim 4 wherein said last-named meansincludes a slide carrying a second cam surface for coaction with saidfirst cam surface.

6. The combination as set forth in claim 2 wherein the surface of saidledge engaged by said portion of the element is inclined in a directionsubstantially toward said first contact.

7. In combination: a base; a first contact mounted on said base; asecond contact; an inherently snap-acting thermostatic element carryingsaid second contact; means mounting said element for movement in a firstdirection from a position at which said contacts are open to a positionat which said contacts are closed, said mounting means permittingmovement of said element in a second direction transversely of saidfirst direction; said element being movable in the direction opposite tosaid first direction from contacts-closed position to contacts-openposition; a ledge adjacent a portion of said element and spaced from thepath of said portion when the element moves from contacts-closed tocontacts-open position, and means for exerting a force against saidelement first in a direction intermediate said first and seconddirections, then in said first direction and then with a lateralcomponent in a direction substantially opposite to said second directionthereby first to bring said portion of the element into overlappingengagement with said ledge, then to snap said portion off said ledgewhereby said second contact snaps into engagement with said firstcontact and then to wipe said second contact against said first contact.

8. The combination as set forth in claim 7 wherein said guided meanscomprises a headed shank; the head of said shank engaging said elementand the shank lying within an aperture provided by said element.

9. The combination as set forth in claim 8 wherein said head provides afirst cam surface; and said last-named means includes a member providinga second cam surface for coaction with said first cam surface.

10. The combination as set forth in claim 9 wherein said head provides acatch for reception of said member to retain said element in said secondposition until released.

11. The combination as set forth in claim 7 wherein the surface of saidledge engaged by said portion of the element is inclined in a directionsubstantially toward said first contact.

12. In combination: a first electrical contact and a sec ond electricalcontact; a snap-acting thermostatic element responsive to temperaturechange; said element carrying said first contact and being biased formovement along a path from a first position to a second position withrespect to said second contact whereby in said first position saidelement, when it responds to temperature change, biases said firstcontact in a direction from engaging to disengaging position withrespect to said second contact; said first contact, with said element insaid second position, being disengaged from said second contact; meansguided for movement along said path and engageable with said element;said last-mentioned means permitting movement of said element laterallyof said path; a ledge adjacent said element and spaced from the paththereof during movement of the element from said first position to saidsecond position; and means movable against said guided means for firstlaterally moving said element into overlapping engagement with saidledge, for then moving a portion of said element to said first position,and then moving said element in a direction opposite to the firstlateral motion whereby said element snaps oif said ledge andsaid firstcontact snaps into engagement with said second contact.

13. The combination as set forth in claim 12 wherein the surface of saidledge engaged by said element is in clined in a direction substantiallytoward said first contact.

14. In combination: a snap-acting member carrying a first electricalcontact and snappable from a first condition to a second condition;means mounting said member for movement from a first position to asecond position; a second electrical contact engaged with said firstelectrical contact when said member is in said first condition and saidfirst position; said contacts being disengaged from each other when saidmember is in said second condition or said second position; a ledgeadjacent a portion of said member; said ledge being spaced from the pathof movement of said portion when said member snaps from said firstcondition to said second condition and moves from said first position tosaid second position; said means permitting lateral displacement of saidportion of the member into overlying relation to said ledge; meansresiliently biasing said member in the direction from said firstposition to said second position; and means for applying force againstsaid member, when the latter is in said first condition and said secondposition, for moving said member first laterally and in the directionopposite to the first-named direction to bring said portion intooverlapping engagement with said ledge and for then moving said memberfarther in said opposite direction to snap said portion off the ledgewhereby said second contact snaps into engagement with said firstcontact.

15. The combination as set forth in claim 14 wherein said membercomprises a thermostatic element snappable in response to temperaturechange from said first condition to said second condition.

References Cited in the file of this patent UNITED STATES PATENTS1,677,710 Daniker July 17, 1928 2,467,745 Harrison Apr. 19, 19492,548,678 Obenour Apr. 10, 1951 2,566,720 Dissinger Sept. 4, 19512,622,169 Cataldo et a1 Dec. 16, 1952 2,681,962 Sundt June 22, 19542,743,333 Epstein Apr. 24, 1956 2,810,041 Wills Oct. 15, 1957 2,811,604Cole Oct. 29,1957 2,811,605 Christensen et a1 Oct. 29, 1957 tenant No.2,901,575

UNIIED STATES PATENT OFFICE CERTIFICATE OF CORRECTION August 221959David E. Clarke I It is hereby certified that error appears in the abovenumbered patent requiring correction and that the said Letters Patentshould read as corrested, below.

In the grant,lines 2 Land 3, for "assignor to Texas InstrumentsIncorporated, of Attleboro, Massachusetts, a corporationofMassachusetts," read as'signor to Texas Instruments Incorporated, acorporation of Delaware, -'--3 in the heading to the printedspecification, lines 3., ,4 and 5, for ",assignor to Texas InstrumentsIncorporated, Attleboro; Mass., a corporation of Massachusetts" readassignor to Texas Instruments Incorporated, a corporation of Delawarecolumn 4, line 69, for "engagement" read engagement column 6, line" 6,for "adjust" read adjusts Signed and sealed this. 26th day of April1960.

Attest:

KARL H. AXLINE ROBERT 0. WATSON- Attestijfl'g Officer CommissionerofPatents I UNI'IED STATES PATENT OFFICE CERTIFICATE OF CORRECTIONPatent No. 2,901,575 Angus-b 5,. 3

David E. Clarke It is hereby certified that error -appears in the abovenumbered patent requiring correction and that the said Letters Patentshould read as cor-- rected below. a v

In the gr.ant,lines 2 and 3, for "assignor to Texas InstrumentsIncorporated, of Attleboro, Massachusetts, a corporation ofMassachusetts," read as'signor to Texas Instruments Incorporated, acorporation of Delaware, -'-3 in the heading to the printedspecification, lines 3., 4 and 5, for "assignor to Texas InstrumentsIncorporated, Attleboro; Mass., a corporation of Massachusetts" read'assignor to Texas Instruments Incorporated, a corporation of Delawarecolumn 4, line 69, for "engagetment" read a engagement column 6, line"6, for "adjust" read in adjusts Signed and sealed this 26th day of April1960.

(SEAL) Attest: KARL H.I r a ROBERT C. WATSON Attestijflg OfficerCommissioner off-Patents a

